QRCode class not resizing down between runs

[K9-guardian]

Test:

#!/usr/bin/env python3
import qrcode

qr = qrcode.QRCode(version=None)
qr.add_data('http://chase.com/')
qr.make(fit=True)
img = qr.make_image()
img.save('test1.png')

qr.clear()
qr.add_data('http://srv.prof-morii.net/∼lab')
qr.make(fit=True)
img = qr.make_image()
img.save('test2.png')

qr.clear()
qr.add_data('http://chase.com/')
qr.make(fit=True)
img = qr.make_image()
img.save('test3.png')

Expected: test1.png == test3.png
Actual: test1.png is a smaller size, as test3.png is the same size as test2.png.

This has to do with how the rs_blocks are looked up, but I couldn't figure out the bug.